Push button type circuit breaker with cross-slide



Nov. 22, 1966 MaoDONALD ETAL 3,287,523

PUSH BUTTON TYPE CIRCUIT BREAKER WITH GROSS-SLIDE Filed Nov. 30, 1965 5 Sheets-Sheet 1 7227/ wt INVENTORG 7%5Y77746 07747;

NOV. 22, 1966 MaCDONALD ETAL 3,287,523

PUSH BUTTON TYPE CIRCUIT BREAKER WITH GROSS-SLIDE Filed Nov. 50, 1965 5 Sheets-Sheet 2 N? W fly W W a Nov. 22, 1966 MaCDONALD ETAL 3,287,523

PUSH BUTTON TYPE CIRCUIT BREAKER WITH CROSS-SLIDE Filed Nov. 50, 1965 5 Sheets-Sheet 5 i=r; =---l 7674/ 7; jz yz 4d g I W: 4 g 2 9 M A? fray/1 5145% United States Patent O 3,287,523 PUSH BUTTON TYPE CIRCUIT BREAKER WITH CROSS-SLIDE John MacDonald, Jackson, and Thomas W. Butler, Jr.,

Ann Arbor, Mich., assignors to Mechanical Products,

Inc., Jackson, Mich., a corporation of Delaware Filed Nov. 30, 1965, Ser. No. 510,496 Claims. (Cl. 200-116)- This application relates generally to. circuit breakers and more particularly to a novel trip free ambient temperature compensated aircraft circuit breaker.

Aircraft circuit breakers are required to be as small and light as possible. It is also generally required that aircraft circuit breakers be of trip free construction. Further, it. is desirable that such circuit breakers be compensated for variations inambient temperature. However, trip free and ambient compensating mechanisms heretofore known and used have been relatively large and heavy.

The circuit breaker of the instant invention utilizes a new component geometry featuring a novel cross slide arrangement that achieves trip [free operation.

Ambient temperature compensation is achieved by using a compensating bimetallic element virtually identical to a current responsive bimetallic element and orientating the ambientand current responsive bimetallic elements in parallel relationship.

Accordingly, one object of the instant invention is an improved aircraft circuit breaker.

Another object is an improved ambient temperature compensating circuit breaker.

Another object is an improved trip free aircraft circuit breaker.

Other objects and advantages of the instant invention will be apparent from the following description, claims and drawings, wherein:

FIGURE 1 is a side elevational view of an improved circuit breaker in accordance with the instant invention;

FIG. 2 is a cross sectional view taken substantially along the line 2--2 of FIGURE 1;

FIG. 3 is a cross sectional view taken substantially along the line 33 of FIG. 2;

FIG. 4 is a cross sectional view taken substantially along the line 4--4 of FIG. 2;

FIG. 5 is a view similar to FIG. 4 showing the current responsive and ambient temperature responsive bimetallic blades in the flexed condition;

FIG. 6 is a view similar to FIG. 5 showing a circuit breaker after manual operation;

FIG. 7 is a view taken substantially along the line 7--7 of FIG. 3; and

FIG. 8 is a cross sectional view taken substantially along the line 8-8 of FIG. 3.

As best seen in FIGURE 1, a circuit breaker 10, in accordance with an exemplary constructed embodiment of the instant invention, comprises an enclosure 12 having a pair of terminals 14 and 16 thereon. A threaded ferrule 18 extends exteriorly of the enclosure 12 for.the support of a manual operator 20.

As best seen in FIGURE 2 of the drawings, the enclosure 12 comprises housing portions 22 and 24 that are held together by a plurality of rivets 26. The ferrule 18 is interlocked with the housing portions 22 and 24 to provide a mounting means for the circuit breaker on a panelboard (not shown).

The manual operator 20 has an internal stem portion 30 secured thereto as by a pin 32. The stem 30 extends centrally of the circuit breaker 10, an upper end portion 34 thereof extending into a complementary slot 36 between the housing portions 22 and 24. A spring 40 normally biases the manual operator 20 downwardly as seen in FIG. 2 of the drawings.

A plunger 50 has a central slot 52 therein for the slidable acceptance Otf the stem portion 30 of the manual operator 20. The plunger 50 has a resilient contact carrier 54 secured thereto which in turn supports a movable contact 56. The movable contact 56 is engageable with a fixed contact 58 to complete a circuit through the circuit breaker 10 as will be described.

A helical tension spring 60 is secured to a com p1e mentary bracket 62 on the plunger 50 and to a bracket 68 on the housing portion 22 so as to normally bias the plunger 50 downwardly relative to the housing 12 as seen in FIG. 2.

As best seen in FIG. 3 of the drawings the plunger 50 has a laterally extending slot 70 therein for the acceptance of a slide 72. The slide 72 is movable internally of the plunger 50 under the influence of a current responsive bimetal 74. As best seen in FIG. 7 of the drawings the current responsive bimetal 74 is interlocked with an end portion 76 of the slide 72 to control lateral movement thereof. 4

An end portion 78 of the slide 72 is normally seated on a latch 80 which in turn is secured to an ambient temperature compensated bimetal 82 so as to be controlled thereby. .It is to be noted that the current responsive bimetal 74 has one end portion 84 seated in a complementary seat 86 in the housing 12 and an "opposite end portion 88 that is positioned by a calibration screw 90. Similarly, one end portion 92 of the ambient compensated bimetal 82 is seated in a complementary seat 94 of the housing 12 and an opposite end portion 96 is seated in a complementary seat 98.

As best seen in FIGURES 4, 5, and 6 the stem portion 30 of the manual operator 20 is provided with a notch 100 having an angular cam portion 102 that isengageable with an edge portion 104 of a complemetary slot 105 in the slide 72 so as to bias the slide 72 to the left,

upon downward movement of the manual operator 20, as seen in the drawings, to effect manual opening of the circuit breaker 10.

The stem portion 30 of the manual operator 20 is interlocked with the plunger 50 by a pin that is carried by the plunger 50 and is received in a complementary slot 112 in the stem 30.

As best seen in FIGS. 3 through 6, the circuit breaker 10 is provided with a heater that is supported in complementary seats 122 and 124 in the housing 12. The heater 120 is disposed in closely spaced heat transfer relationship to current responsive bimetals of low current rating 74 to speed up the response thereof to an overload condition. The heater 120 can be connected in series or parallel relationship to the bimetal 74 or eliminated as required by the rating of the circuit breaker.

Closure of the circuit breaker from the condition shown in FIG. 6 of the drawings to the condition shown in FIGS. 2, 3, and 4 of the drawings is effected by upward pressure on the manual operator 20 until the latch 80- snaps under the end portion 78 of the slide 72.

Upon the occurrence of an overload condition the current responsive bimetal 74 flexes as shown in FIG. 5 of the drawings to draw the slide 72 to the left disengaging the end portion 78 thereof from the latch 80. When the slide 72 is disengaged from the latch 80 the plunger 50 is free to move downwardly relative to the housing 12 of the circuit breaker 10 and stem 30 of the manual operator 20 under the bias of the spring 60. It is to be noted that, as seen in FIG. 5, the circuit breaker is trip free in operation since the manual operator 20 can be held in the closed position without effecting the ability of the circuit breaker to trip due to an overload condition.

It is also to be noted that deflection of the current responsive bimetal 74 due to a high ambient temperature condition is compensated by a similar fiexure of the ambient compensating bimetal 82 which in turn moves the latch 80 to a compensating position.

Electrical continuity through the circuit breaker is established from the terminal 14 to the current responsive bimetal 74 via a pigtail 150. A pigtail 152 connects the opposite end 88 of the current responsive bimetal to the movable contact 56 (FIG. 2) which in turn is electrically engageable with the fixed contact 58. The fixed contact 58 is electrically connected to the terminal 16.

It is to be understood that the specific construction of the improved circuit breaker herein disclosed and described is presented for the purpose of explanation and illustration and is not intended to indicate limits of the invention the scope of which is defined by the following claims.

What is claimed is:

1. An electrical circuit breaker comprising an insulating housing,

a pair of terminals extending exteriorly of said housa fixed contact connected to one of said terminals,

9 an elongated current responsive bimetallic element in said housing having its end supported thereby, one end of said current responsive bimetal being electrically connected to the other of said terminals,

- a latch supported by said housing,

a plunger having a movable electrical contact thereon engageable with said fixed contact and electrically connected to the other end of said current responsive bimetal to complete an electrical circuit through said circuit breaker,

a slide carried by said plunger and extending generally normally to said current responsive element, said slide having one end engaged with an intermediate portion of said current responsive bimetal and the other end engaged with said latch, means supporting said slide for movement upon deflection of said current responsive bimetal thereby to affect effecting disengagement of said slide from said latch permitting said plunger to move to the contacts open condition, and a manual operator engageable with said plunger to bias said plunger and movable contact to the contacts closed condition, said manual operator having means engageable with said slide to effect movement thereof relative to said latch to effect manual opening of said contacts.

2. A circuit breaker in accordance with claim 1 including an ambient temperature compensating bimetal disposed in spaced parallel relation to said current responsive bimetal and operative to move said latch to compensate said circuit breaker for changes in ambient temperature.

3. A circuit breaker in accordance with claim 2 including an ambient temperature compensating bimetal disposed in spaced parallel relation to said current responsive bimetal and of like configuration thereof, said compensating bimetal being operative to move said latch to compensate said circuit breaker for changes in ambient temperature.

4. A circuit breaker in accordance with claim 1 wherein said manual operator extends through said plunger so as to be engageable with said slide.

5. A circuit breaker in accordance with claim 1 wherein said current responsive bimetal has a slot therein for the acceptance of an end portion of said slide whereby lateral movement of said bimetal effects like movement of said slide.

References Cited by the Examiner UNITED STATES PATENTS 2,185,525 10/1937 Sachs a- 200-116 2,187,606 1/1940 Jackson et a1. 200l16 2,972,664 2/1961 Furnas et a1. 200116 3,210,501 10/1965 Clarke 200-116 3,141,941 7/1964 Dew 200-116 3,223,803 12/1965 Walters 200124 BERNARD A. GILHEANY, Primary Examiner.

H. B. GILSON, Assistant Examiner. 

1. AN ELECTRICAL CIRCUIT BREAKER COMPRISING AN INSULATING HOUSING, A PAIR OF TERMINALS EXTENDING EXTERIORLY OF SAID HOUSING, A FIXED CONTACT CONNECTED TO ONE OF SAID TERMINALS, AN ELONGATED CURRENT RESPONSIVE BIMETALLIC ELEMENT IN SAID HOUSING HAVING ITS END SUPPORTED THEREBY, ONE END OF SAID CURRENT RESPONSIVE BIMETAL BEING ELECTRICALLY CONNECTED TO THE OTHER OF SAID TERMINALS, A LATCH SUPPORTED BY SAID HOUSING, A PLUNGER HAVING A MOVABLE ELECTRICAL CONTACT THEREON ENGAGEABLE WITH SAID FIXED CONTACT AND ELECTRICALLY CONNECTED TO THE OTHER END OF SAID CURRENT RESPONSIVE BIMETAL TO COMPLETE AN ELECTRICAL CIRCUIT THROUGH SAID CIRCUIT BREAKER, A SLIDE CARRIED BY SAID PLUNGER AND EXTENDING GENERALLY NORMALLY TO SAID CURRENT RESPONSIVE ELEMENT, SAID SLIDE HAVING ONE END ENGAGED WITH AN INTERMEDIATE PORTION OF SAID CURRENT RESPONSIVE BIMETAL AND THE OTHER END ENGAGED WITH SAID LATCH, MEANS SUPPORTING SAID SLIDE FOR MOVEMENT UPON DEFLECTION OF SAID CURRENT RESPONSIVE BIMETAL THEREBY TO AFFECT EFFECTING DISENGAGEMENT OF SAID SLIDE FROM SAID LATCH PERMITTING SAID PLUNGER TO MOVE TO THE CONTACTS OPEN CONDITION, AND A MANUAL OPERATOR ENGAGEABLE WITH SAID PLUNGER TO BIAS SAID PLUNGER AND MOVABLE CONTACT TO THE CONTACTS CLOSED CONDITION, SAID MANUAL OPERATOR HAVING MEANS ENGAGEABLE WITH SAID SLIDE TO EFFECT MOVEMENT THEREOF RELATIVE TO SAID LATCH TO EFFECT MANUAL OPENING OF SAID CONTACTS. 